Titanium carbide nickel composition process

ABSTRACT

Dense, homogeneous compositions having (a) a density in excess of 95 percent of theoretical and (b) an average grain size less than 10 microns and consisting of: 1. 80-97 PERCENT BY VOLUME OF TITANIUM CARBIDE AND 2. 3-20 PERCENT BY VOLUME OF NICKEL, THE NICKEL BEING PRESENT MAINLY AS A BINDER PHASE UNIFORMLY DISTRIBUTED AT THE GRAIN BOUNDARIES, ARE USEFUL AS CUTTING EDGES FOR CUTTING TOOLS.

aniels Oct. 2, 1973 [54] TITANTUM CARBIDE-NICKEL 3,455,682 7/1969 Barbas75/204 COMyOSITHON PROCESS 3,490,901 1/1970 Hachisuka 75/213 X [75]Inventor: Alma U. Daniels,Wilmington,Del. [73] Assignee: E. 1. du Pontde Nemours and Com- Primary Emmi"e' Le1a"d Sebastian panxwilmingtonq DeLAttorney-Gerald A. l-lapka 22 Filed: m. 28, 1972 .1 7 [21] Appl No 230 00 ABSTRACT Related [1.5. Application Data [62] Division Of Ser. N0.828,699, May 28, 1969, Pat. N0. Dense homogeneous compositions having(a) a de sity in excess of 95 percent of theoretical and (b) an averagegrain size less than 10 microns and consisting of: [52] U.S. Cl 75/204,75/213, 75/221, 1 0 97 percent by Volume of titanium carbide and 75/225,75/226 2. 3-20 percent by volume of nickel, the nickel being [51] ll lt.Cl BZZf 3/16 present i l as a binder phase uniformly [58] Field ofSearch 75/204, 213, 221, distributed at the grain boundaries are usefmas 75/225, 226 cutting edges for cutting tools.

[56] References Cited UNITED STATES PATENTS 3,45l,79l 6/l969 Meadows75/204 X 4 Claims, N0 Drawings TITANIUM CARBIDE-NICKEL COMPOSITIONPROCESS This is a division of application Ser. No. 828,699 filed May 28,1969, now US. Pat. No. 3,674,443.

BACKGROUND ln the past, many attempts have been made to make strongdense compositions which have small average grain sizes by sinteringtitanium carbide and nickel compositions. Such titanium carbide-nickelbodies have very large average grain sizes and the nickel has not beenuniformly distributed, possibly due to inadequate wettingof the titaniumcarbide by the nickel, and furthermore the bodies have been lacking instrength. To overcome this problem, it has been the practice to usemolybdenum along with the nickel. See Swinehart, Cutting Tool MaterialsSelection A.S.T.M.E., Dearborn, page 89 (1963). The use of molybdenumalong with the nickel gives improved wetting of the carbide phase andenables a strong sintered composition to be made.

It has now been discovered that strong, dense titanium carbide-nickelbodies can be prepared in the absence of molybdenum when the process astaught in the instant invention is employed.

SUMMARY OF THE INVENTION It has been found that dense titaniumcarbide-nickel bodies with average grain sizes smaller than 10 micronscan be prepared when particular process conditions are used.

Thus, the invention relates to the following compositions of matter:homogeneous compositions having (a) a density in excess of 95 percent oftheoretical and (b) an average grain size less than 10 micronsconsisting of:

1. 80-97 percent by volume of titanium carbide and 2. 3-20 percent byvolume of nickel, the nickel being present mainly as a binder phaseuniformly distributed at the grain boundaries, substantially all of saidbinder phase having a thickness of less than 0.5 micron.

These compositions demonstrate exceptional advan tages over sinteredtitanium carbide-nickel compositions and as a result of theirexceptional properties the compositions of this invention are useful ascutting tools in machining materials such as cast iron and alloy steel.

The above compositions can be made by:

l. intimately milling together a mixture of fine titanium carbide andnickel powder in a hydrocarbon oil and separating, drying and screeningthe powder in a non-oxidizing atmosphere;

[1. charging in a non-oxidizing atmosphere the titanium carbide-nickelpowder to a grpahite mold provided with close fitting graphite pistonsand in either sequence (a) applying to the powder by means of saidpistons a pressure of -500 psi and (b) introducing the mold into avacuum furnace preheated to a temperature in the range of from 1,000C.to 1,475C.;

III. heating said mixture under vacuum to a selected temperature in therange of from 1,350C. to 1,475C. in a period of time ranging from about2 minutes to 20 minutes while maintaining a pressure of from 0-500 psi;

lV. maintaining the final temperature and pressure of Step III for aperiod of time ranging from zero minutes to 5 minutes;

V. maintaining the temperature of Step Ill and applying to the sample bymeans of the graphite pistons a pressure in the range of from 500 psi to4,000 psi for a period of time ranging from 2 minutes to 6 minutes; and

Vl. thereafter immediately releasing the pressure on the pistons,removing the die from the furnace and rapidly cooling the resultingtitanium carbide-nickel composition.

DETAILED DESCRIPTION Starting Materials Titanium carbide is used in thecompositions of this invention in'amounts ranging from -97 percent byvolume. At least 80 volume percent titanium carbide is required toprovide adequate hardness. Preferred amounts of carbide range from -95percent by volume to achieve an optimum balance of strength andhardness.

Titanium carbide can be obtained commercially or can be synthesized bymethods well known to the art. The titanium carbide should be finelydivided, that is it should have a particle size of less than 5 micronsand preferably less than 2 microns. If the starting material isappreciably larger than 5 microns in particle size it can be pre-groundto reduce its size to that which is acceptable. Of course the milling ofthe components of this invention, which is carried out to obtain a highdegree of homogeneity, will result in some comminution of the carbideand the other starting component, nickel.

Nlckel is used in the compositions of this invention in amounts rangingfrom 3-20 percent by volume. At least 3 volume percent of nickel isrequired to provide adequate strength. The preferred amounts of nickelare 5-15 percent by volume since an optimum balance of strength andhardness are achieved in this range.

The starting materials used in the compositions of this invention shouldbe pure. In particular it is desired to exclude impurities such asoxygen which tends to have deleterious effects on the densecompositions. On the other hand minor amounts of many impurities can betolerated with no appreciable loss of properties. Thus, the metal cancontain small amounts of other metals such as titanium, zirconium,tantalum or niobium as minor impurities, although low melting metalslike lead should be excluded. Small amounts of carbides other thantitanium carbide, such as several percent of tungsten carbide, which issometimes picked up in grinding, can be present. Even oxygen can betolerated in small amounts such as occurs when titanium carbide has beenexposed to air resulting in a few percent of titanium oxy-carbide.However, after the powder components have been milled together and arein a highly reactive state, oxidation, particularly of the metals,occurs easily and should be avoided.

PROCESS OF MANUFACTURE The manner in which the compositions of thisinvention are prepared is important, because the characteristics of thecompositions are achieved in part at least as a result of the manner inwhich they are prepared. Thus the use of tine-grained starting materialsand thorough milling of the mixed components are directly related to thefine grain size and uniform homogeneity of the compositions. Otherprecautions which should be observed in preparing the compositions whichhave important effects on the products are:

l. the prevention of excessive contamination from grinding media andmoisture or oxygen in the air;

2. hot-pressing or presintering under conditions which permit the escapeof volatile materials prior to densification;

3. avoiding undue absorption of carbon from pressing molds by limitingtheir contact under absorptionpromoting conditions;

4. avoiding excessive component recrystallization and resultantsegregation by avoiding prolonged subjection to very high temperatures.

1. Milling and Powder Recovery Milling of the components, tohomogeneously intermix them and obtain very fine grain sizes, is carriedout according to the practices common in the art. lf roller milling isemployed, optimum milling conditions will ordinarily involve a millhalf-filled with a grinding medium such as cobalt bonded tungstencarbide or alumina balls or rods, a liquid medium such as a hydrocarbonoil, an inert atmosphere, grinding periods of from a few days to severalweeks, and powder recovery also in an inert atmosphere. The recoveredpowder is ordinarily dried at temperatures of around l50300C. undervacuum, followed by screening and storage when desirable in an inertatmosphere. Other methods of milling, such as vibratory milling can alsobe used in preparing the powders.

2. Consolidation The compositions of this invention are ordinarilyconsoildated to dense, pore-free bodies by sintering under pressure.Consolidation is ordinarily carried out by hot pressing the mixedpowders in a graphite mold under vacuum.

The hot pressing process consists of loading milled and dried powderinto a graphite mold or die provided with close fitting graphite pistonsand subjecting it to a pressure of -500 psi, applied to the pistons bymeans of hydraulically activated rams, inserting the mold into theheated zone (l,0O0C.-l,475C.) of a vacuum hot press, thus allowingvolatile impurities to escape before the composition is densified. Fullpressure (SOD-4,000 psi) is then applied to the sample at or nearmaximum temperature (l,350l,475C.) employed for a period of time rangingfrom 2 minutes to 6 minutes.

The pressure is then released and the mold containing the densified bodyis immediately ejected from the heated zone of the hot press and cooledrapidly in the course of a few minutes to dull red heat while stillunder vacuum.

Maximum or goal temperatures for hot pressing range between 1,350C. and1,475C. depending on the amount of nickel which is present. Thetemperatures will ordinarily be about l,400C. Full pressures used duringhot pressing ordinarily range between 500 and 4,000 psi, with lowpressures being used in combination with lower temperatures forcompositions with a high nickel content. Conversely, higher pressuresand temperatures are employed for compositions low in nickel.

As would be expected, at higher temperatures and pressures, some of thenickel may tend to squeeze out of the compositions when pressure isapplied. This tendency can be compensated for by starting with a littlemore nickel than is desired in the final body when operating at a hightemperature and pressure. By this procedure, some of the nickel will besqueezed out during pressing, leaving the body with the desired metalcontent. Generally speaking, appreciable squeeze-out of metal is to beavoided not only because it changes the composition but also because themetal causes sticking to and damaging of the molds.

It is important that during hot pressing, the compositions not be heatedto a goal temperature for a period of time which is much in excess ofthat required to eliminate porosity and achieve density. Such highertemperatures or longer times can result in excessive grain growth,coarsening of the structure, the development of secondary porosity dueto recrystallization, or in the formation of undesirable phases.

The products of this invention are ordinarily subjected to pressure atmaximum temperature for 2-6 minutes after which the product isimmediately removed from the hot zone. The resultant bodies are finegrained, homogeneous, essentially pore-free, and are characterized byhigh hardness and excellent transverse rupture strength.

Characteristics of the Compositions In addition to characterizing thecompositions of this invention on the basis of the components discussedabove, the compositions can also be characterized on the basis of theirstructural characteristics, i.e., fine grain size and homogeneity.

The dense bodies of this invention are characterized as having a fineaverage grain size smaller than 10 microns and preferably smaller than 5microns in average grain diameter. Moreover, the grain size is uniformthroughout the compositions and there is essentially no porosity in thedense compositions of this invention. The fine grain size and lowporosity of dense compositions of this invention contribute greatly toits hardness and thus result in bodies which are exceptionallyabrasion-resistant. For example, cutting tools made from dense bodies ofthis invention resist abrasion when coming in contact with the hardcarbide inclusions that are found in cast iron.

Distribution of the titanium carbide and nickel in dense bodies of thisinvention is uniform and homogeneous, and, generally speaking, any areal00 microns square which is examined microscopically at 1,000Xmagnification will appear the same as any other area microns squarewithin conventional statistical distribution limits. The nickel ispresent mainly as a binder phase uniformly distributed at the grainboundaries, substantially all of said binder having a thickness of lessthan 0.5 microns, in contrast to compositons prepared by conventionalsintering where the nickel is largely present as heterogeneouslydistributed inclusions in a coarse-grained weak body. The combination offine grain size and homogeneity of distribution of the components indense bodies of this invention results in bodies which are resistant tothermal shock both as regards shattering and as regards surfaceheat-cracking.

The products may contain small amounts of iron, cobalt, tungstencarbide, alumina, and other impurities, which are generally picked upduring the milling process. When metallic impurities are present, theywill generally consititue less than about 1 percent by volume of thetotal composition. When alumina inserts are used during milling, forexample in a vibratory mill, there may be as much as 5 percent by volumeof alumina present.

The products of this invention will have actual densities in excess of95 percent of theoretical, preferably in excess of 98 percent oftheoretical. Theoretical density for any given composition is determinedby the following equation:

pt 4.95 V 8.90 V wherein pt theoretical density in grams per cubiccentimeter;

V desired volume in cubic centimeters of titanium carbide per cubiccentimeter of product;

V,,,, desired volume in cubic centimeters of nickel per cubic centimeterof product.

A comparison of actual density to theoretical density is of course anindication of the degree of porosity.

EXAMPLES The invention will be better understood in reference to thefollowing examples wherein parts are by weight unless otherwise noted.

EXAMPLE 1 This is an example of a composition containing 93 volumepercent titanium carbide and 7 volume percent nickel.

The titanium carbide used is a fine powder with a specific surface areaof 3 m /g., as determined by nitrogen adsorption. An electronmicrographs shows that the titanium carbide grains are approximately 2microns in diameter, and are clustered in the form of loose aggregates.The carbon content is 19.0 percent andthe oxygen analysis indicates atitanium dioxide content of about 2.5 percent.

The nickel used is a fine powder containing 0.15 percent carbon, 0.07percent oxygen, and less than 300 parts per million iron. The specificsurface area of the nickel powder is 0.48 m lg. and its X-raydiffraction pattern shows only nickel which has a crystallite size of150 millimicrons as calculated from line broadening. Under the electronmicroscope, the powder appears as polycrystalline grains, 1 to 5 micronsin diameter.

The powders are milled by loading 8,300 grams of cyclindrical 6 percentcobalt-bonded tungsten carbide inserts, one-fourth inch long andone-fourth inch in diameter in a 1.8 liter steel rolling mill that iscompletely lined with 6 percent cobalt-bonded tungsten carbide. Theinserts have been previously worn in" so that contamination of powderbatches with tungsten carbidecobalt will be kept to a few percent. Themill is charged with a mixture of 500 ml. of Soltrol 130 (a saturatedparaffinic hydrocarbon with a boiling point of approximately 130C), 230grams of the titanium carbide and 31.2 grams of the nickel as abovedescribed.

The mill is then sealed and rotated at 90 rpm for 5 days. The mill isthen opened and the contents emptied while keeping the milling insertsinside. The mill is then rinsed out with Soltrol" 130 several timesuntil essentially all of the milled solids are removed.

The milled powder and liquid are then transferred to a vacuum evaporatorand the excess hydrocarbon is decanted off after the suspended materialhas settled. The wet residual cake is then dried under vacuum with theapplication of heat until the temperature within the evaporator isbetween 200 and 300C, and the pressure is less than about 0.1 mls. ofmercury. Thereafter, the powder is handled entirely in the absence ofair.

The dry powder is passed through a mesh screen in a nitrogen atmosphere,and then stored under nitrogen and sealed in plastic containers.

A consolidated billet is prepared from this powder by hot pressing thepowder in a cylindrical graphite mold having a cylindrical cavity 1 inchin diameter and which is equipped with opposing close-fitting graphitepistons. One piston is held in place in one end of the mold cav ity,while 22 grams of the powder is dropped into the cavity under nitrogenand evenly distributed by rotating the mold and tapping it lightly onthe side. The upper piston is then put in place under hand pressure. Theassembled mold and contents are then placed in the vacuum chamber of avacuum hot press. The mold is held in a vertical position and thepistons extending above and below are engaged between opposite graphitegrams of the press under pressure of about psi. Within a period of aminute, the mold is raised into the hot zone of the furnace at 1,000C.,and at once the temperature of the furnace is increased while thepressure is maintained at 100 psi during the heat-up period. Thetemperature is raised from 1,000C. to 1,400C. in about 4 minutes, andthe temperature of the mold is then held at l,400C. for another 2minutes to ensure uniform heating of the sample. A pressure of 4,000 psiis applied to the billet through the pistons for 4 minutes. The pressureis then released and the mold and contents are immediately moved out ofthe furnace into a cool zone and cooled to dull red heat in about 5minutes.

After further cooling, the mold and contents are removed from the vacuumfurnace and the billet is re moved from the mold and sand-blasted toremove any adhering carbon.

The hot pressed billet is found to be essentially nonporous, having novisible porosity under 1,000X magnification. An electron micrograph at20,000X magnification on a sample etched with a mixture of hydrofluoric,nitric and sulfuric acids shows a homogeneous composition having anaverage grain size of about one micron, with a nickel-rich binder phaseuniformly distributed at the grain boundaries and having a thickness of0.05 to 0.3 microns. Few of the grains exceed 2 or 3 microns in size.The density is 99 percent of the theoretical density.

X-ray diffraction analysis reveals primarily a sharp, strongface-centered cubic type pattern with atomic spacing of 4.323 Angstromsindicating titanium carbide, and also diffraction lines showing thepresence of free nickel.

Chemical analysis shown, in addition to titanium, carbon and nickel, thepresence of about 2.7 percent of tungsten and 0.l5 percent of cobalt.The tungsten and cobalt are presumably picked up from attrition of themilling inserts and mill lining. The billet, which is 1 inch indiameter, and about 0.30 inch in thickness, is cut so that a pieceslightly larger than one-half inch square is removed from the center.Strips 0.070 inch in thickness are cut from the material remaining toeach side of the center piece, and are further cut into 0.070 X 0.070inch square bars, for testing transverse rupture strength. Otherportions of the billet are used for indentation hardness tests and forother product characterizations. The transverse rupture strength asmeasured by breaking the 0.070 X 0.070 inch test bars on aninesixteenths inch span is about 21 1,000 psi. The hardness of thebillet is 93.0 on the Rockwell A scale.

The square center piece is finished as a cutting tip to 1/2 X l/2 X 3/16inch, and the corners are finished with a one thirty-second inch radius,a style known in the industry as SNG-432.

The tip is used to turn a cylinder of Class 30 grey cast iron at a speedof 1,250 surface feet per minute, a depth of 0.050 inch and a feed of0.005 inch per revolution. After ten minutes the wear land on the flankof the cutting edge is only 0.006 inch deep, which is only half theflank wear measured on a commercial titanium carbide based cutting tipafter minutes turning under the same condiitons. When used to mill 4,340steel having a Brinnell hardness number of 340 at 1,000 surface feet perminute, a width of cut of 2 inches, a depth of 0.050 inch and a feed of0.0057 inch per revoultion, for a single tooth 6 inches diameter millinghead, two corners of the insert run an average distance of 24 inchesbefore failing by chipping. Two corners of a commercial titanium carbidebased cutting tip tested under the same condition give an averagecutting distance of only 16 inches before failing due to chipping. Thusthe composition of the invention shows a considerable improvement overconventional titanium carbide based'compositions, both with respect towear and chip resistance in machining operations on two importantclasses of metal.

EXAMPLE 2 The procedure of Example 1 is repeated, except that theproportions of the components are changed to give a powder containing 86volume percent of titanium carbide and 14 volume percent of nickel.

A dense body made by hot pressing this powder as described in Example 1is found to have a transverse bend strength 207,000 psi and a Rockwell Ahardness of 92.2 Examination of an electron micrograph at amagnification of 20,000X on a sample etched as in Example 1 shows ahomogeneous composition having an average grain size of about 0.8microns and a nickelrich binder phase uniformly distributed at the grainboundaries and having a thickness of 0.l to 0.5 microns. The esnsity is98.5 percent of the theoretical density.

An SNG-432 cutting tip made from the hot pressed body is found to yieldexcellent results in the semifinishing turning of Class 30 gray castiron and in the finish milling of Class 30 gray cast iron.

EXAMPLE 3 The procedure of Example 1 is used, changing the proportionsof the components to give a powder containing 97 volume percent oftitanium carbide and 3 volume percent of nickel. The powder is hotpressed as described in Example 1, modifying the conditions as follows.The sample in the mold is pressed at 500 psi, before being introducedinto the hot zone of the vacuum hot press at 1,200C. It is brought to1,475C. maintaining the pressure on the sample at 500 psi during theheat-up period of about 3 mintes. After holding at l,475C. for 5 minutesto ensure uniform heating of the sample, the pressure is increased from500 psi to 4,000 psi and this pressure and temperature of l,475C. aremaintained for a further 6 minutes. The pressure is then released andthe mold and contents are immediately moved out of the furnace into acool zone and cooled to dull red heat in about five minutes.

The resulting dense body is found to have a transverse rupture strengthof 155,000 psi and a Rockwell A hardness of 93.5. Electron micrographexamination of a sample etched as in Example 1 shows a homogeneouscomposition havingan average grain size of about 3 microns and anickel-rich binder phase uniformly distributed at the grain boundariesand having an average thickness of 0.02 to 0.2 microns. The density is97 percent of the theoretical density.

A seal vane in a centrifugal pump for pickling acid in a steel plant ismade from the above composition, and after being in service for 6months, inspection of the part shows very little wear or corrosiveattack and the part is returned to service.

UTILITY The pressed products show excellent performance as cutting toolsand have advantages over conventional TiC-based tools in certainapplications such as turning cast iron and milling alloy steel. Theproducts can also be used as wear parts and refractory and corrosionresistant parts in high temperature equipment.

I claim:

l. A method for making a homogeneous composition consisting of to 97percent by volume of titanium carbide and 3 to 20 percent by volume ofnickel and having (a) an average grain size smaller than l0 microns, (b)a nickel-rich binder phase uniformly distributed at the grainboundaries, substantially all of said binder phase having a thickness ofless than 0.5 micron, and (c) a density in excess of percent of thetheoretical density, comprising the steps of:

I. intimately milling together a mixture of fine grain titanium carbideand nickel powder in a hydrocarbon oil, separating, drying and screeningthe powder in a non-oxidizing atmosphere,

ll. charging in a non-oxidizing atmosphere the titanium carbide-nickelpowder to a mold provided with close-fitting pistons and in eithersequence (a) applying to the powder by means of said pistons a pressureof 0-500 psi, and (b) introducing the mold into a vacuum furnacepreheated-to a temperature in the range of from l,000C. to l,475C.;

Ill. heating said mixture under vacuum to a selected temperature in therange of from 1,350C. to 1,475C. in a period of time ranging from about2 minutes to 20 minutes while maintaining a pressure on said mixture offrom 0-500 psi;

IV. maintaining the final temperature and pressure of Step ll for aperiod of time ranging from zero minutes to 5 minutes;

V. maintaining the temperature of Step IV and applying to said mixture apressure of from 500 psi to 4000 psi for a period of time ranging from 2minutes to 6 minutes; and

VI. thereafter immediately releasing the pressure on the piston,removing the mold from the furnace and rapidly cooling the resultingtitanium carbidenickel composition.

2. The process of claim 1 wherein Step III the selected finaltemperature is about 1,400C., the time is about 4 minutes, and thepressure on the sample is between and 200 psi.

3. The process of claim 1 wherein the pressure on the sample in Step Vis about 4,000 psi.

4. A method for making a homogeneous composition consisting of 80 to 97percent by volume of titanium carbide and 3 to 20 percent by volume ofnickel and having (a) an average grain size smaller than 10 microns, (b)a nickel-rich binder phase uniformly distributed at the grainboundaries, substantially all of said binder phase having a thickness ofless than 0.5 micron, and (c) a density in excess of 95 percent of thetheoretical density, comprising the steps of:

l. intimately milling together a mixture of fine titanium carbide andnickel powder in a hydrocarbon oil, separating, drying and screening thepowder in a non-oxidizing atmosphere;

ll. charging in a non-oxidizing atmosphere the titanium carbide-nickelpowder to a mold provided with close-fitting pistons and in eithersequence (a) applying to the powder by means of said piston a pressureof 100 to 200 psi, and (b) introducing the the resulting titaniumcarbide-nickel composition to dull red heat'in' about 5 minutes.

2. The process of claim 1 wherein Step III the selected finaltemperature is about 1,400*C., the time is about 4 minutes, and thepressure on the sample is between 100 and 200 psi.
 3. The process ofclaim 1 wherein the pressure on the sample in Step V is about 4,000 psi.4. A method for making a homogeneous composition consisting of 80 to 97percent by volume of titanium carbide and 3 to 20 percent by volume ofnickel and having (a) an average grain size smaller than 10 microns, (b)a nickel-rich binder phase uniformly distributed at the grainboundaries, substantially all of said binder phase having a thickness ofless than 0.5 micron, and (c) a density in excess of 95 percent of thetheoretical density, comprising the steps of: I. intimately millingtogether a mixture of fine titanium carbide and nickel powder in ahydrocarbon oil, separating, drying and screening the powder in anon-oxidizing atmosphere; II. charging in a non-oxidizing atmosphere thetitanium carbide-nickel powder to a mold provided with close-fittingpistons and in either sequence (a) applying to the powder by means ofsaid piston a pressure of 100 to 200 psi, and (b) introducing the moldinto a vacuum furnace preheated to a temperature in the range of from1,000* to 1,475*C.; III. heating said mixture under vacuum to about1,400*C. in 2 to 20 minutes while maintaining a pressure on said mixtureof from 100 to 200 psi; IV. maintaining the temperature and pressure ofStep III for about 2 minutes; V. maintaining a temperature of Step IVand applying a pressure on said mixture of about 4,000 psi for about 4minutes; and VI. immediately releasing the pressure on the pistons,removing the mold from the furnace and cooling the resulting titaniumcarbide-nickel composition to dull red heat in about 5 minutes.